1. Field of the Invention
The present invention relates to portable terminal devices, and more specifically, the invention relates to portable terminal devices such as note-type personal computers and electronic pocketbooks used as the nodes of wireless LAN systems, in which the covers of the devices are opened when used.
2. Description of the Related Art
Local Area Networks (LANs) have a structure in which the system is located in specified areas, for example, on the sites or premises of users in such a manner that communications are performed by mutually connecting various individual devices such as personal computers, servers, facsimiles, and the like. This system is used for various purposes such as gaining access to the database of servers via personal computers or gaining access to devices of other LAN systems via a communication network connected to the LAN system.
The connections between devices in LAN systems are very often made by wire communication channels. However, there are wireless LAN systems in which parts of the connections are make by wireless communication channels. In the wireless LAN systems, it is not necessary to mechanically connect individual devices to the LAN communication networks. Alternatively, the wireless LAN system can be used by registration, regardless of locations, as long as the devices are located in areas to which wireless radio waves can reach. Accordingly, this is a significantly useful system.
FIGS. 8A and 8B show the front view of a prior art portable terminal device and the side view thereof, respectively. A portable terminal device 50 has a main body 52 including a data entry keyboard 51 and the like, a cover 53 openably and closably attached to the main body 52, a liquid crystal display 54 disposed on the inner side of the cover 53, and a monopole antenna 55 for a wireless LAN system. In addition, a board having a ground, on which a calculation processing unit, a memory unit, and the like are mounted, is disposed inside the main body 52, although the board is not shown in the figure. When the portable terminal device 50 is used, the cover 53 attached to the main body 52 is opened and the monopole antenna 55 is set up. When carried with a user, the cover 53 is closed in such a manner that the cover 53 and the main body 52 are put together, and the monopole antenna 55 is collapsed along the main body 53.
Since a beam 56 in a horizontal direction can be obtained by the monopole antenna 55 in the above portable terminal device 50, the monopole antenna 55 can sufficiently satisfy requirements as the directional characteristics of an antenna. Meanwhile, when carried with a user, the monopole antenna 55 is collapsed and the portable terminal device 50 is placed in a bag, or a pocket. As a result, since the monopole antenna 55 collapsed alongside of the main body 52 exists as a protruding item, the antenna is a nuisance to the user, and it also tends to be easily broken. To solve these problems, another prior art portable terminal device has been developed as shown in FIGS. 9A and 9B.
FIGS. 9A and 9B show the front view of another prior art portable terminal device and the side view thereof, respectively. When compared with the portable terminal device 50 (shown in FIGS. 8A and 8B), in a portable terminal device 60, instead of disposing a monopole antenna, a wireless card 62 having a monopole antenna 61 is connected to a PCMCIA slot (not shown) of the main body 52, by which a wireless communication function is given to the portable terminal device 60.
In each of the above conventional portable terminal devices, however, since the portable terminal device and the wireless card are separated, there is a problem in that it is inconvenient for a user to carry such a type of portable terminal device with him.
In addition, since the wireless card is directly connected to the main body having the ground, there is a problem in that the directivity of the monopole antenna toward the main body side deteriorates significantly. Furthermore, there is a problem in that the directivity of the monopole antenna is influenced by digital noise from the main body.
To overcome the above described problems, preferred embodiments of the present invention provide a portable terminal device having the directivity of an antenna in a desired direction without increasing the size and weight of the portable terminal device.
One preferred embodiment of the present invention provides a portable terminal device comprising: a main body including a data entry keyboard; a cover openably and closably attached to the main body and establishing a connecting portion between the main body and the cover; a display disposed on the inner side of the cover; a chip antenna disposed on the cover at a place other than the display and opposed to the connecting portion; and the chip antenna comprising a ceramic base body, a conductor disposed at least either inside the base body or on a surface thereof, and a feeding terminal disposed on a surface of the base body and connected to one end of the conductor.
According to the above described structure and arrangement, the chip antenna is disposed on the cover at a place other than the display and opposed to the connecting portion. When the cover is opened to use the portable terminal device, the chip antenna is thereby positioned as far as possible from the main body having a ground. As a result, the gain of the chip antenna can be substantially uniform in the range of 360xc2x0. Therefore, a wireless communication channel in which a portable terminal device is stabilized in the range of 360xc2x0 can be provided.
In addition, since the chip antenna includes the ceramic base body and the conductor formed at least either inside the base body or a surface thereof, the chip antenna can be miniaturized by a wavelength-shortening effect. As a result, the cover of the portable terminal device and the chip antenna can be integrated by disposing the antenna on the inner side of the cover of the portable terminal device. Accordingly, this arrangement contributes to miniaturization of the portable terminal device and weight reduction thereof.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.